Fin rolls for tube mills



Aug. 21, 1962 INVENTOR. STANLEY L. NITKIEKNJL; BY I ATTORN United States Patent 3,050,101 FIN ROLLS FOR TUBE MILLS Stanley L. Nitkiewicz, Toledo, Ohio, assignor to Abbey Etna Machine Company, Perrysburg, Ohio, a corporation of Ohio Filed Mar. 22, 1961, Ser. No. 97,536 4 Claims. (Cl. 15354) This invention relates to tube mills in which a strip or ribbon of sheet metal is gradually formed into a tube, the abutting edges of which are welded to provide a closed tube. More particularly, however, this invention relates to the fin roll employed in the tube forming operation.

In tube mills, the metal ribbon is fed first between a series of forming rolls which are arranged in pairs, one pair being horizontally spaced from the next pair and ese forming rolls gradually curl or form the flat sheet metal ribbon into tube form with the free edges spaced from each other. After the strip in partial tube form passes through the series of forming rolls, they pass to a series of fin rolls. There may be three sets of fin rolls, each set having an upper and lower roll between which the partially formed tube passes. These rolls form the partial tube into tube form with the free edges in close juxtaposition and in position for the welding operation. Each set of fin rolls has a pair of curved rolls of substantially the form of the tube passing therethrough, and one is equipped with a central fin through which the gap between the opposed edges of the partial tube passes. As the tube approaches the Welding station, the fin rolls serve gradually to force the free edges toward each other and into abutting engagement so that a proper weld can be made.

Heretobefore the fin ring carried by the fin roll and against which the free edges of the tube engages, has been an element rigid with and rotatable with the roll with which it is associated. The edges of the tube are brought against the sides of the fin ring and as the tube advances, the fin ring decreases in diameter so that the fin rolls gradually and successively press the edges of the tube toward each other. Considerable diificulty and trouble has been occasioned with the use of the fixed fin ring because of the great pressure that is imposed on the free edges of the tube, forcing these edges against the fin ring. Not infrequently as a result these tube edges become distorted. Consequently when welding is performed, an unsatisfactory weld takes place because the tube edges do not perfectly engage each other.

An object of this invention is to overcome the above ditficulties and to provide a fin roll structure by which the edges in an undistorted condition are brought together at the welding station so that a satisfactory and efiicient weld is achieved.

Another object is to produce a fin roll for tube mills in which the fin ring or annulus against which the free edges of the tube press, is free to rotate independently with respect to the body of the fin roll so that the fin annulus or ring can rotate at whatever speed of linear movement is imparted to the tube regardless of a diflFerence in the speed of rotation of the body of the fin roll.

Other objects and advantages of the invention will hereinafter appear, and for purposes of illustration but not of limitation, an embodiment of the invention is shown on the accompanying drawings in which FIGURE 1 is an end elevation of a fin roll, the other roll of the set being shown by broken lines and the tube passing th'erebetween being also shown by broken lines;

FIGURE 2 is an end elevation of a fin roll partly in section and with the fin ring or annulus removed;

FIGURE 3 is a transverse sectional view on the line 33 of FIGURE 1; and

Patented Aug. 21 1962 FIGURE 4 is a sectional view of the fin ring or an nulus.

The illustrated embodiment of the invention comprises a fin roll 10 with which is associated a forming roll 11, each of these rolls being independently driven and between these two rolls passes the tube 12, the free edges of which are spaced apart, having been delivered to such set of rolls from a series of forming rolls which have gradually formed a flat strip or ribbon of sheet metal into the partial tube form. It will be understood that after the tube has passed through a series of pairs of fin rolls, the tube reaches the welding station where the tube is progressively welded as it advances. It is important that the free edges of the partial tube be brought squarely together without any distortion or damage. This invention overcomes difliculties heretofore encountered in which the free edges of the partially formed tube as it passes through the sets of fin rolls become distorted or otherwise damaged.

As shown, the fin roll 10 is fixed to a driving shaft 13 and this shaft is driven at the same speed that the shaft on which the forming roll 11 is mounted so that the rolls of each set rotate at the same speed. As shown, the fin roll 10 is secured to the driving shaft 13 by a key 14. The fin roll consists of a pair of axially spaced flange members 15 which have curved wall portions which engage the tube and impose a squeezing pressure thereon to gradually bring the free edges of the partial tube closer together. The fin roll sets vary as they approach the welding station in order to achieve the desired tube shape with the free edges in abutment.

Formed on the inner faces of each of the flange members 15 is -a groove 16 and fitting the groove in the flange members 15 is a spacer ring 17 which is likewise keyed to the shaft 13- by the key 14. The spacer ring cooperates with the adjacent edges of the flange members to provide a groove 18 in which is disposed a fin ring or annulus 19 which fits the groove somewhat loosely so that it can rotate therein relatively to the flange members 15.

As shown, the fin ring or annulus 19 is formed with tapered converging side walls 20 and with a curved peripheral surface portion 21. It will be understood that the thickness of the fin rings '19 varies as the fin roll sets approach the welding station, the nearer to the welding station the thinner will be the fin ring 19 so as to bring the free edges of the tube closer and closer together until they finally abut one. with the other.

Extending through the flange members 15 and the spacer ring 17 is a series of bolt and nut assemblies 22 thereby rigidly to secure the several parts together to insure their rotation as a unit.

From the above description, it will be manifest that as the tube 12 advances, the fin ring or annulus can rotate in response to the friction imposed thereon at a speed different from that of the flange members 15. Thus eventhough the flange members 15 rotate at a faster speed than the edge portion of the tube being formed, the fin ring or annulus can rotate at Whatever speed of linear movement is imparted to the tube 12. This eliminates any damage to the free edge portions of the tube which heretofore has been found to result due to the difierences in the movement of the tube as compared to the movement of the fin ring 19. As a consequence, when the tube reaches the welding station, the free edges are in perfect condition and can abut properly against each other so as to achieve a satisfactory and etficient weld.

Numerous changes in details of construction and arrangement and operation may be effected without departing from the spirit of the invention, especially as defined in the appended claims.

What I claim is:

1. A fin roll for tube mills comprising a body structure having upwardly and-outwardly curved side wall portions for tube engagement, the tube being disposed with the separated flee edges thereof facing toward the central portion of the body structure, and a fin ring mounted on the body structure between the side wall portions and in such manner as to rotate freely and independently thereof, said ring extending into the space between the tube edges for abutment thereby whereby the fin roll is rotated by engagement therewith of the tube edges according to the linear speed of the tube and at a difierent speed than that of the body structure of the fin roll.

2. A fin roll for tube mills comprising a body structure having upwardly and outwardly curved side wall portions for tube engagement, the tube being disposed with the separated free edges thereof facing toward the central portion of the body structure, a central annular groove in the body structure and a fin ring mounted on the body structure in said annular groove between the side wall portions and in such manner as to rotate freely and independently thereof, said ring extending into the space between the tube edges for abutment thereby whereby the fin roll is rotated by engagement therewith 4 of the tube edges according to the linear speed of the tube and at a ditferent speed than that of the body structure of the fin roll.

3. A fin roll as claimed in claim 2 in which the body structure comprises a pair of flange parts, each flange part having an annular groove in its inner face, a spacer ring fitting the grooves of said flange parts and forming with the adjacent flange parts a circular groove in which References Cited in the file of this patent UNITED STATES PATENTS Gossett et a1. May 30, 1916 Berg May 24, 1921 FOREIGN PATENTS 264,5 34 Great Britain June 30, 1927 

